The present invention relates to a plug socket for electrically connecting a cable or the like having a stripped wire portion with a flat plug, where the plug socket comprises a sleeve portion having an approximately U-shaped cross-sectional configuration and having side walls that are bent inwardly and between which a flat plug is insertable from one end, and further comprising a crimp portion that is provided with first and second claw-shaped clamping sections, wherein the first clamping section is provided for crimping the conductive stripped wire cable portion, and the second clamping strip is provided for crimping the insulation of a cable.
Many embodiments of such plug sockets are known and are widely used primarily in the "white" household appliance industry. The plug sockets, which serve as cable sockets or terminals, are connected to an electrical conductor by crimping, in other words by being squeezed together and deformed; this provides an electrically good conducting and, due to the solder-free manufacture, also a relatively corrosion resistant connection. A flat plug that is to be contacted is accommodated by the sleeve portion, which is provided with an interlocking mechanism in the form of a detent or a point-type raised portion, which cooperates with an opening in the flat plug. The sleeve portion essentially comprises a base plate and two oppositely disposed and projecting side walls that are bent over in a curved manner over the base plate in order to achieve a linear contact on the upper side of a flat plug. The known plug sockets primarily differ from one another with regard to the structural shape of the base plate and the bent side walls, the purpose of which is to minimize frictional forces during insertion of a flat plug while still achieving adequate reliability of the electrical connection.
However, a drawback of the heretofore known plug sockets is that despite a reliable contact of the plug socket and a flat plug, the electrical connection is frequently adversely affected by loosening of the cable, which is secured by crimping. The cause for this is the tensile stress of the crimp connection caused by the movablility of a cable, as a result of which the crimp connection can again be released. It is therefore known in the state of the art to provide the free end of a clamping strip with a projection that during the crimping is introduced into a rectangular opening of the crimping portion and is compressed on the underside of the crimping portion, resulting in an interlocking. The drawback of this is that due to the opening not only does a weakening of the strength of the plug socket occur, but also significant heating-up in the contact zone when high currents are present due to the transition resistance, which is increased by the opening. A further drawback is that non-plated contact regions of the opening come into contact with the normally plated upper surface, which can lead to unfavorable contact corrosion. A further drawback of the known plug sockets is that when tensile stress results, for example when the flat plug is pulled out, there occurs at the transition location between the cable insulation and the exposed or stripped wire portion a bending or deformation of the clamping strip that crimps the stripped wire portion; this can lead to shearing off of the stripped wire portion at the insulation sheathing.
It is therefore an object of the present invention to improve a plug socket of the aforementioned general type such that a reliable interlocking and an increased holding force of the crimp connection of a cable is provided, while at the same time such a plug socket is easy and economical to produce.